The present invention relates to a shell structure, and more particularly to a shell structure for a signal sensing and transmitting device.
The bicycle is considered as a transporting device as well as an entertainment tool in leisure time. A wireless speedometer for a bicycle is developed and becomes popular. Such a speedometer can provide information including the speed of the bicycle, the distance that the bicycle has moved, etc. Referring to FIG. 1, a wireless speedometer 1 is mounted on a bicycle 10. The wireless speedometer 1 includes a magnet 11, a signal sensing and transmitting device 13, and a calculating and indicating device 15. The magnet 11 is mounted on a spoke 12 of the bicycle 10. The signal sensing and transmitting device 13 is mounted on the folk 16 of the bicycle 10. The signal sensing and transmitting device 13 includes a reed switch (not shown). The position of the signal sensing and transmitting device 13 is corresponding to that of the magnet 11 so that the magnet 11 can pass through the signal sensing and transmitting device 13 while the bicycle 10 is moving. When the magnet 11 passes through the signal sensing and transmitting device 13, an on/off signal will be generated by the reed switch. A control signal is then generated and transmitted by the signal sensing and transmitting device 13 to the calculating and indicating device 15 mounted on the handlebar 14. The calculating and indicating device 15 includes a microprocessor and a liquid crystal display (not shown). According to the number and the frequency of the received control signals and the diameter of the front wheel 17 of the bicycle 10, the speed and the moving distance of the bicycle 10 can be calculated by the microprocessor and indicated on the liquid crystal display.
FIGS. 2(a) and 2(b) respectively illustrate two kinds of conventional signal sensing and transmitting devices. In FIG. 2(a), the conventional signal sensing and transmitting device includes the main body of the signal sensing and transmitting circuit 21, and the battery 22. The main body of the signal sensing and transmitting circuit is received within the shell body 231. The shell cover 232 is mounted to the shell body after the main body of the signal sensing and transmitting circuit 21 has been put into the shell body 231. The shell cover 232 is fastened on the shell body by the screws 24. A water-resistant ring 235 is mounted between the shell cover 232 and the shell body 231 to keep the circuit away from moisture. The shell cover 232 includes a battery hole 233 for receiving therein the battery 22. The battery 22 is fastened by the battery cover 234. To keep the battery 22 away from moisture, a water-resistant ring 236 is mounted between the battery cover 234 and the shell cover 232.
In FIG. 2(b), the conventional signal sensing and transmitting device include the main body of the signal sensing and transmitting circuit 71 and the battery 72. The assembly of the shell body 731, the main body of the signal sensing and transmitting circuit 71, the shell cover 732 including the battery hole 733, the battery 72, the water-resistant ring 736, and the battery cover 734 are similar to that of the elements shown in FIG. 2(a) except the combination of the shell body 731 and the shell cover 732. They are integrated by an ultrasonic jointing method instead of screwing. Accordingly, the water-resistant ring between the shell body and the shell cover is saved. Furthermore, since the ultrasonic combination method consumes less time that of the screwing process, the assembling efficiency is increased. However, the main body of the signal sensing and transmitting circuit 71, especially the antenna, may be damaged by the vibration generated during the ultrasonic jointing process. As a result, the yield is reduced. Furthermore, the main body of the signal sensing and transmitting circuit 71 and the battery 72 must be respectively covered and fastened by the shell cover 732 and the battery 734. The assembling process is still troublesome.
It is then attempted by the Applicant to solve the above-mentioned problems.
An object of the present invention is to provide an easily-assembled shell structure for a signal sensing and transmitting device of a speedometer of a bicycle.
Another object of the present invention is to increase the yield and reduce the cost of manufacturing a shell structure for a signal sensing and transmitting device of a speedometer of a bicycle.
According to the present invention, a shell structure of a signal sensing and transmitting device adapted to be used with a wireless speedometer for a bicycle is provided. A main body of a signal sensing and transmitting circuit and a battery is received within the shell structure. The shell structure includes a shell body. The shell body includes an opening for being inserted therethrough the main body of the signal sensing and transmitting circuit and the battery. The shell body also includes a receiving space for receiving therein the main body of the signal sensing and transmitting circuit and the battery. The shell structure further includes a fastening lip for covering the opening of the shell body and fastening the main body of the signal sensing and transmitting circuit and the battery within the shell body.
The shell body is preferably pillared and hollow for forming therein the receiving space. Preferably, the opening is formed on a top portion of the shell body. More particularly, the fastening lip may be circular while the shell body is cylindrical. In such a situation, both the shell body and the fastening lip may be threaded for screwing the fastening lip on the shell body.
According to another aspect of the present invention, a flexible fixer is preferably formed on the shell body, and a recess corresponding to the flexible fixer is formed on the fastening lip for receiving therein the flexible fixer.
According to still another aspect of the present invention, the shell body and the fastening lip may be jointed by a bolt.
Preferably, a water-resistant ring is mounted between the fastening lip and the shell body for keeping the receiving space from moisture. Such a water-resistant ring can be made of rubber or silica gel.
Preferably, both the fastening lip and the shell body include threaded portions respectively so that the fastening lip can be screwed on the shell body. In such a situation, the water-resistant ring is mounted between the threaded portions.
According to another aspect of the present invention, the water-resistant ring can also be mounted around the rim of the opening or at the junction of the shell body and the fastening lip.
The main body of the signal receiving and transmitting circuit preferably includes a transmitting antenna, a print circuit board (PCB), and a PCB holder for holding the PCB.
A battery supporter is preferably mounted on the PCB holder for supporting the battery.
Preferably, the shell body further includes a fixing ring for fixing the signal sensing and transmitting device on a bicycle.
The shell body is preferably formed integrally.
The present invention may best be understood through the following description with reference to the accompanying drawings, in which: